Look like a pantograph for the 3d model. I suppose it is something like that but maybe to reduce the coin or medal. Maybe too you have only one reduce size and it do it automatically without regulation because you don't have this possibility.
Do you have all machine's parts?

Without seeing everything closer. I suspect that it may be a type of pantograph used for engraving gilloche patterns or a cycloidal engine which is an instrument for engraving bank notes, etc., with complicated patterns of interlacing lines; also called a Geometric lathe. The decorative borders found on US currency are drawn (in part) by a cycloidal engine.

In the video I can't see a cutting head where contact with the workpiece would be, hovever that part could be missing.

Hard to say, of course! The tool appears to fit into the square hole on the block of metal that's attached to the moving business end above the wooden circle. There's a set-screw hole there. Examining the whole thing, there's no obvious shadows or unexplained holes from a missing part, though. At lunch, I'll insert the pic that shows this.

For me it is a reduce machine for coin or medal.
On the turn table you put the big model and on the other way you have the good size mold.
Now to be sure you can ask the "money of Paris" of course it is in France but I believe he can help you.
You can send an email to the conservator of British Museum too, they are a department of coin.

In the video I can't see a cutting head where contact with the workpiece would be, however that part could be missing.

The mechanism is touching the wood now; this is adjustable, but maybe the missing tool needs to be resting with the weight from above pushing it down? Also, the position of the tool holder would determine the length of the "cut", it seems to me.

used for engraving gilloche patterns or a cycloidal engine which is an instrument for engraving bank notes, etc., with complicated patterns of interlacing lines; also called a Geometric lathe. The decorative borders found on US currency are drawn (in part) by a cycloidal engine.

That's pretty close. Here's what the director of the Bureau of Engraving and Printing had to say:

Quote:

I checked with one of our engravers and he confirms itís an old ruling machine. It would have been used to incise lines and circles (using the disk turntable configuration) into the metal plates.